Point-of-use robotic sensors for simultaneous pressure detection and chemical analysis

Abstract

The development of sensors for monitoring hazardous materials in security and environmental applications has been increasing in the last few years. In particular, organophosphates pose a serious health threat that affects the food and agriculture industries. Hence, their rapid on-site detection is highly desired, especially through remote robotic sampling that can minimize the exposure of humans to these hazardous chemicals. To handle sample collection, a robotic manipulator requires tactile feedback, to ensure that no damage will be done to either the robot or the other object in contact due to excessive force. To provide tactile feedback, porous polydimethylsiloxane pressure sensors based on a capacitive mechanism were chosen here, and integrated with enzyme-based electrochemical sensors specific for organophosphate compounds (e.g. methyl paraoxon). This results in a hybrid physical-chemical sensing glove that can simultaneously measure the pressure and chemical target without interference between the two sensors. Our pressure sensors showed 455% relative capacitance change per 10 kPa applied pressure, with an average sensitivity (S) of 0.057 AE 0.004 kPa À1 in the 3-20 kPa range and a maximum sensitivity of 0.30 AE 0.08 kPa À1 in the o0.05 kPa range. The chemical biosensors showed a detection range of 20-180 lM for methyl paraoxon in the liquid phase. We have thus combined low-cost chemical and pressure sensors together on disposable, retrofitting gloves, and demonstrated simultaneous tactile sensing and organophosphate pesticide detection in a point-of-use robotic field platform that is scalable, economical, and adaptable for different security, environmental, and food-safety applications.

Organic Bulk Heterojunction Infrared Photodiodes for Imaging Out to 1300 nm

“…The photodiode semiconductors are a blend of the copolymer 10 comprised of a bridgehead olefin (C=CPh) substituted cyclopentadithiophene (CDT) donor and pyridal-[2,1,3]selenadiazole (PSe) acceptor (C=CPhCDT-co-PSe) and the molecule [6,6]-phenyl-C 61 -butyric acid methyl ester (PC 61 BM). The polymer has a peak absorption at λ = 950 nm, and the devices show the photoabsorption edge to λ = 1300 nm as shown in Figure 1.…”

Extending Porous Silicone Capacitive Pressure Sensor Applications into Athletic and Physiological Monitoring

“…Soft material sensors are typically divided into two classes: piezoresistive and capacitive [ 18 ]. Resistive sensors were developed for many applications due to their typically high sensitivity to pressure and strain [ 19 , 20 , 21 , 22 ], and significant durability has been demonstrated in some high sensitivity systems in recent times [ 23 ]. Capacitive sensors, with their restriction of conductive elements to electrodes for interrogation of dielectric layers [ 3 , 24 ], have potential for mechanical robustness, particularly with large deformation.…”

“…Capacitive sensors, with their restriction of conductive elements to electrodes for interrogation of dielectric layers [ 3 , 24 ], have potential for mechanical robustness, particularly with large deformation. This class has demonstrated fast responsiveness [ 4 , 25 , 26 ], good linearity [ 4 , 5 , 25 , 26 ], low hysteresis [ 4 , 5 , 25 , 26 ], durability [ 4 , 27 , 28 ], and insensitivity to changes in temperature and humidity [ 28 , 29 ], but may lack sensitivity [ 20 , 22 ]. For wearable applications, where sensors are expected to undergo many high strain or compression cycles, and even impact, this robustness may be particularly important.…”

Multifunctional Self‐Powered E‐Skin with Tactile Sensing and Visual Warning for Detecting Robot Safety

“…With the development of the sensors, the tactile sensing is also able to provide information about the force and positions between the robots and the interacted objects. [ 6 ] Thus, various kinds of the pressure sensors have been designed and applied as different force sensing interfaces. [ 7,8 ] Although the pressure sensors are attracting great attention in robot field, the limited sensing function, rigid structure and complicated back‐end data processing still raise the requirements of further advancement in the robot safety detection.…”